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After a review over past experiments and theoretical requirements from low-energy flavour physics, we argue that the possibility of low-mass leptoquarks (LQ) cannot be fully excluded due to the assumptions made in the measurements.…

High Energy Physics - Phenomenology · Physics 2021-08-18 Li-Gang Xia

In the context of $SU(2)_L\times U(1)$ dimension six operators we study the potential of the LHeC to provide information on top quark effective interactions. We focus on single antitop production and how it is affected not only by the…

High Energy Physics - Phenomenology · Physics 2015-06-03 I. A. Sarmiento-Alvarado , Antonio O. Bouzas , F. Larios

Search strategies for the third-generation leptoquarks (LQs) are distinct from other LQ searches, especially when they decay to a top quark and a $\tau$ lepton. We investigate the cases of all TeV-scale scalar and vector LQs that decay to…

High Energy Physics - Phenomenology · Physics 2022-02-01 Arvind Bhaskar , Tanumoy Mandal , Subhadip Mitra , Mohit Sharma

Leptoquarks are ubiquitous in several extensions of the Standard Model and seem to be able to accommodate the universality-violation-driven $B$-meson-decay anomalies and the $(g-2)_\mu$ discrepancy interpreted as deviations from the…

High Energy Physics - Phenomenology · Physics 2022-05-18 Tomas Husek , Kevin Monsalvez-Pozo , Jorge Portoles

Depending on the assumptions on the power corrections to the exclusive b -> s l+ l- decays, the latest data of the LHCb collaboration - based on the 3 fb^-1 data set and on two different experimental analysis methods - still shows some…

High Energy Physics - Phenomenology · Physics 2016-06-29 T. Hurth , F. Mahmoudi , S. Neshatpour

A search for leptoquarks produced singly and in pairs in proton-proton collisions is presented. We consider the leptoquark (LQ) to be a scalar particle of charge -1/3$e$ coupling to a top quark plus a tau lepton ($\mathrm{t}\tau$) or a…

High Energy Physics - Experiment · Physics 2021-06-22 CMS Collaboration

We study the pair production of scalar top-quark partners decaying to a top-quark pair plus large missing energy at the LHC, a signature which appears in numerous models that address outstanding problems at the TeV-scale. The severe…

High Energy Physics - Phenomenology · Physics 2013-12-09 Radja Boughezal , Markus Schulze

We studied the collider phenomenology of third-generation scalar leptoquarks at the Large Hadron Collider (LHC) with a 14 TeV center-of-mass energy. The analysis focuses on leptoquarks decaying exclusively into top quarks and tau leptons,…

High Energy Physics - Phenomenology · Physics 2025-01-14 Debabrata Sahoo , Rameswar Sahu , Kirtiman Ghosh

Some interpretations of $R_{D^{(*)}}$ anomaly in $B$ meson decay using leptoquark (LQ) models can also generate top quark decays through Flavor Changing Neutral Current (FCNC). In this work we focus on two LQs, i.e. scalar $S_1$ and vector…

High Energy Physics - Phenomenology · Physics 2020-01-08 Tae Jeong Kim , Pyungwon Ko , Jinmian Li , Jiwon Park , Peiwen Wu

Following the updated measurement of the lepton flavour universality (LFU) ratio R_K in B -> Kll decays by LHCb, as well as a number of further measurements, e.g. R_K* by Belle and B_s -> mu mu by ATLAS, we analyse the global status of new…

High Energy Physics - Phenomenology · Physics 2020-04-22 Jason Aebischer , Wolfgang Altmannshofer , Diego Guadagnoli , Meril Reboud , Peter Stangl , David M. Straub

We calculate the $\Lambda_b \to \Lambda_c \ell \nu$ form factors and decay rates for all possible $b\to c \ell\bar\nu$ four-Fermi interactions beyond the Standard Model, including nonzero charged lepton masses and terms up to order…

High Energy Physics - Phenomenology · Physics 2019-03-27 Florian U. Bernlochner , Zoltan Ligeti , Dean J. Robinson , William L. Sutcliffe

We show that a modification of the model with a low energy scalar leptoquark state carrying hypercharge $Y=7/6$ allows to accommodate both $R_K<1$ and $R_{K^\ast}<1$, through loop effects, consistent with recent observations made at LHCb.…

High Energy Physics - Phenomenology · Physics 2018-06-01 Damir Bečirević , Olcyr Sumensari

Leptoquarks (LQs) have been extensively studied in the context of $B$ anomalies. When $U(1)_{L_\mu-L_\tau}$ is introduced to a scalar LQ model with the LQ $S_1$ charged under the new symmetry, $S_1$ primarily couples to the third-generation…

High Energy Physics - Phenomenology · Physics 2023-10-05 Chuan-Hung Chen , Cheng-Wei Chiang

At hadron colliders, the search for R-parity violating supersymmetry can probe scalar masses beyond what is covered by pair production processes. We evaluate the next-to-leading order SUSY-QCD corrections to the associated stop or sbottom…

High Energy Physics - Phenomenology · Physics 2011-01-27 A. Alves , O. Eboli , T. Plehn

We present the results of a search for leptoquark (LQ) pairs in (85.2 +- 3.7) pb^{-1} of p anti-p collider data collected by the D0 experiment at the Fermilab Tevatron. We observe no evidence for leptoquark production and set a limit on…

High Energy Physics - Experiment · Physics 2008-11-26 D0 Collaboration , V. M. Abazov

We present a study on the impact of scalar leptoquarks on the semileptonic decays of $ \Lambda_b$, $\Sigma_b $ and $\Xi_b $. To this end, we calculate the differential branching ratio and lepton forward-backward asymmetry defining the…

High Energy Physics - Phenomenology · Physics 2017-09-06 K. Azizi , A. T. Olgun , Z. Tavukoglu

We present a comprehensive review of physics effects generated by leptoquarks (LQs), i.e., hypothetical particles that can turn quarks into leptons and vice versa, of either scalar or vector nature. These considerations include discussion…

High Energy Physics - Phenomenology · Physics 2016-08-03 I. Doršner , S. Fajfer , A. Greljo , J. F. Kamenik , N. Košnik

The cross sections for the formation of scalar resonances, leptoquarks or squarks, in electron/positron-proton collisions at HERA are presented including next-to-leading order QCD corrections. Depending mildly on the mass of the resonances,…

High Energy Physics - Phenomenology · Physics 2007-05-23 T. Plehn , H. Spiesberger , M. Spira , P. M. Zerwas

We present results for the next-to-leading order QCD corrections to the production and semi-leptonic decays of a top quark pair in hadron collisions, retaining all spin correlations. To evaluate the virtual corrections, we employ…

High Energy Physics - Phenomenology · Physics 2009-11-18 Kirill Melnikov , Markus Schulze

The scalar and vector leptoquark pair production cross sections in hadronic collisions are calculated. In a model independent analysis we consider the most general C and P conserving couplings of gluons to both scalar and vector leptoquarks…

High Energy Physics - Phenomenology · Physics 2016-09-06 J. Blümlein , E. Boos , A. Kryukov